colors: Check for None via direct pointer comparison instead of object equality to avoid FutureWarning from numpy.
colors: Check for None via direct pointer comparison instead of object equality to avoid FutureWarning from numpy.

xiwei-zhang/vigra,mmuellner/vigra,xiwei-zhang/vigra,capturePointer/vigra,ThomasWalter/vigra,funkey/vigra,timoMa/vigra,mmuellner/vigra,dagophil/vigra,capturePointer/vigra,ThomasWalter/vigra,dstoe/vigra,xiwei-zhang/vigra,timoMa/vigra,xiwei-zhang/vigra,dstoe/vigra,xiwei-zhang/vigra,funkey/vigra,cha007/vigra,cha007/vigra,funkey/vigra,capturePointer/vigra,mmuellner/vigra,funkey/vigra,cha007/vigra,dagophil/vigra,dagophil/vigra,timoMa/vigra,dagophil/vigra,ThomasWalter/vigra,capturePointer/vigra,cha007/vigra,capturePointer/vigra,capturePointer/vigra,mmuellner/vigra,funkey/vigra,timoMa/vigra,xiwei-zhang/vigra,ThomasWalter/vigra,capturePointer/vigra,dstoe/vigra,timoMa/vigra,timoMa/vigra,mmuellner/vigra,dstoe/vigra,xiwei-zhang/vigra,dagophil/vigra,funkey/vigra,dstoe/vigra,dstoe/vigra,dstoe/vigra,cha007/vigra,timoMa/vigra,dagophil/vigra,cha007/vigra,mmuellner/vigra,ThomasWalter/vigra,ThomasWalter/vigra,mmuellner/vigra,funkey/vigra,cha007/vigra,ThomasWalter/vigra,dagophil/vigra